Ovens for treating compressed coal briquettes



P 1966 e. KLEINBERG 3,274,702

OVENS FOR TREATING COMPRESSED COAL BRIQUETTES Filed May 31, 1963 2 Sheets-Sheet 1 Inve ntor:

GUSTAVE KLyBERG y Attorney Sept. 27, 1966 G. KLEINBERG 3,274,702

OVENS FOR TREATING COMPRESSED COAL BRIQUETTES Filed May 31, 1963 2 Sheets-Sheet 2 Inventor:

Attolr-ney United States Patent 1 Claim. (c1. 34-171 The present invention relates to the thermal treatment of fuel blocks or fuel briquettes or sorted coals adapted to undergo a transformation by heat at a comparatively low temperature of from 250 to 450 C., for instance, and more particularly to the production of non smoke-producing fuel blocks such as spheros or ovoids from coal agglomerates made with various binders such as pitch, bitumen, resins, sulfite lyes from paper-mills, starch etc.

Briquetted calibrated fuel materials are generally of a brittle nature at temperatures in the range of 100 C. and can withstand only low weights without being deformed. They harden at higher temperatures, for instance at 300 or 400 C., and may then reach a high resistance, of the order of 100 kg./sq. crn. Such brittleness at the starting of the heating process, raises difficult problems in connection with the construction of the oven for carrying out the thermal treatment, since the agglomerated blocks cannot be piled up in layers of sufiicient height without the danger of the underlying blocks being crushed.

Oven assemblies for drying various products, such as cereals and coal, for instance, are well known, which may or may not comprise oppositely disposed battles, with the product to be dried being traversed by at least one heating gas flow. Some of the devices of the known art provide simply a zig-zag shaped chute for the discharge of the product, while others use mechanical means for regulating the discharge. The known equipments however all have the drawback of not allowing a uniform treatment of the fuel blocks and a delivering of a substantial amount of broken blocks. In order to obviate these drawbacks and to increase the economical efficiency by eliminating, practically, the breakage of the briquettes, this invention provides an improved oven for the thermal treatment of fuel briquettes which, while being of a simple and economical construction, delivers a product of a high homogeneity, the hot gases used for the thermal treatment of the blocks being distributed in a perfectly uniform manner throughout the thickness of the load.

According to the invention there is provided, an oven for the thermal treatment of fuel briquettes, blocks, or sorted coals, which includes an upright enclosure provided at its upper end with an inlet opening for the products to be treated and at its lower end with a discharge opening for the treated products and other, secondary products, which may possibly be formed. Bafile members are located in the oven, including superposed sloping partitions, connected, alternatively, to two oppositely, disposed walls at their upper edge, and defining a free axial central space, with means for introducing into the enclosure a flow of gases through the products. There is, thereby, provided, from the top down, a heating zone, a treatment zone and a cooling zone for the products, the oven assembly being arranged such that the vertical spacing between two succeeding, external or internal, baffle members, is smaller than the thickness of the material layer which would cause the crushing of the products underlying the layer. The battle members have their 3,274,702 Patented Sept. 27, 1966 "ice lower edges located substantially on a same vertical line, the upper edges of the set of external battle members being substantially at the same levels as the lower edges of the set of inner baffle members, openings being formed immediately under the partitions forming the baffles, so that, at the top, the heating gas enters under a baffle member and flows out below one of the baffle members at the upper level. In the middle portion, the treating gas penetrates below a baflle member and flows out below one of the baffle members of the upper level. Finally, none of the gas outlets occur at the level of a gas inlet or outlet.

Preferably, the oven enclosure includes a cylindrical ring, the bafile plates therein being arranged in the shape of truncated cones. These plates or partitions may be solid or provided with perforations.

Preferably, also, the inlet and outlet openings for the treating gases are located just below the partitions so as to be protected thereby. They may be placed in alternating array below each one of the plates located on the same side or, below certain of the plates only, or on two of the oven walls facing each other.

In certain cases where, during the treatment, a volatilisation of the condensable coal-tars would occur, it is desirable to provide, at the outlet openings for the gases, means for recovering said coal-tars.

Because of the arrangement of the oven according to the invention, the charge introduced at the top of the oven slips down uniformly therethrough as the treated products are extracted at the lower end, while the active gases, which are uniformly distributed in the free space below the baffle plate overlying their corresponding input openings, fiow in an amount several times the volume of the enclosed material resting on the baflle plates between an inlet opening and a discharge opening in such a manner that the contact betweeen the products to be treated and the hot gases is as intimate as possible, and the gases diffuse very uniformly through the whole enclosure of each level. The battle members, suitably spaced over the whole height of the oven, reduce the crushing load exerted on the ball-shaped blocksor boulets--of the lower layers, so that they do not suffer any distortion and/or are not crushed by the weight of the overlying layers, even though, as is the case with the pitch and bitumen bound coal blocks, these soften down at the heating temperature and harden up only at a higher temperature, i.e. in the treatment or reaction zone of the oven.

The cylindrical shape as described for the oven is, of course, optional and is given by way of example only: any other shapefor instance that of a parallelepipedon may be equally suitable. The essential point lies in the fact that the blocks or calibrated coal lumps move down from the upper level to the lower level in a vertically disposed enclosure, merely under the effect of gravity, to be discharged at the lower level, that the path followed is in staggered order and that the thermal treat ment gases are caused to pass several times through the whole depth of the slowly descending material, and thus give up thereto the major part of their heat, without leaving open any other path of lesser resistance, to bypass, partly or totally, the load therein.

The invention will be best understood from the following description and appended drawings, wherein:

FIGURE 1 is a diagrammatic vertical, cross-sectional view of an embodiment, by way of example, of an oven for treating ball-shaped coal blocksor bouletsaccording to the invention.

FIGURE 2 is a horizontal cross-section through line IIII of FIG. 1.

FIGURE 3 is a diagrammatic vertical, cross-sectional view of an alternative embodiment of the oven according to the invention.

Referring to the drawings, and more particularly to FIGURES 1 and 2, there is shown an oven in accordance with the invention, consisting of two-coaxial vertical cylinders 1 and 2, the outer cylinder 1 being divided into six stages or levels 2 1 through 26. The height h of each stage may vary according to the nature and, especially, to the resistance of the compressed blocks to be treated. In the case of ovoids of low resistance which tend to soften down during heating, as well as with those using a binder such as pitch or bitumen, this height should not generally exceed one meter and should preferably be from 50 to 60 cm.

In the annular space provided between cylinders 1 and 2 are inserted bafile members including partitions 3 and 4 shaped as truncated cones and secured, alternatively, onto the inner outer surface of the wall of outer cylinder 1 and onto the wall of inner cylinder 2, respectively, the arrangement comprising partitions 41 through 46 and partitions 51 through 56, .a respective one of each of the last named partitions for each stage. The lower free edges of partitions 41-46 and 51-56 lie approximately on the same virtually vertical cylinder. Every second partition, namely partitions 5'1, '53 and 55 is formed with holes 5 for the passage of the gases, holes 5 being dimensioned so as not to allow the passage therethrough of the products treated.

Below each of partitions 41-46, there is provided an inlet or an outlet opening for the treating gases. In the example illustrated, the oven comprises inlet openings 82, 83 and 85 located, respectively, below partitions 42, 43 and 45 and outlet openings 91, 24 and 96, located respectively, below partitions 41, 44, 46. Openings 82 and 83 connect to the hot gas supplies, respectively, one being at the heating temperature lower than the treating temperature, while opening 85 connects to a cooling gas supply. On the other hand, the outlet openings 91, 94 and 96 are connected either to a vent duct, or to a. reheater for the combustion air of the hearth generating the active hot gases.

For clarity of the drawings, neither the discharge conduits, nor the heat exchangers have been represented in the figures.

Between the partitions baffles 43 and 44, the wall of the inner cylinder 2 is pierced with holes 9 to allow the passage of the gases to an axially located shaft 10 provided with an adjusting flap valve 11 for the complete closing thereof, when necessary. A funnel 12 ending in a discharge conduit 13 is located inside the inner cylinder 2, below the perforated area 9. This cylinder is closed at its upper end by a cap 14, whereas the outer cylinder 1 is fitted, at its upper end, with a loading hopper 15 and, at its lower end, with a discharge hopper 16 under which there is secured a revolving hearth 1-7.

During the operation of the oven, this revolving hearth '17 is effective in causing the treated products to be uniformly discharged, the products in the course of treatment sliding uniformly down through the battle arrangement, as they are being discharged, following a zig-zag path, under the effect of gravity brought about by the suitable inclination of partitions 41-46 and 5156. The amounts of the products to be treated corresponding to the amounts discharged are progressively loaded into the oven.

It will be apparent that by means of the arrangement described, the treating gases which ensure, successively, the heating up of the ovoids, then their treatment proper at the reaction temperature and finally the cooling thereof, twice cross the fuel layer as limited by the height of a corresponding stage, following the paths indicated in solid lines 18a, 18b, and 180. If desired, by opening the flap valve 11, a more or less substantial amount of the treating gases may be discharged through the central shaft 10 (path 18d shown in dashed lines), the condensed tar material being collected through funnel 12 and discharged through conduit 13.

In the alternative embodiment illustrated in FIGURE 3, the general arrangement of the oven is substantially similar to that previously described (the same elements in the figure being designated by identical reference numbers). The only difference lies in that the inlet openings 83 and discharge openings 94 for the hot reaction gases proper are substituted by perforated areas 104 and 103 formed in the inner cylinder 2, above and below funnel 12, respectively, that hot gases being introduced into the space defined by said cylinder and conduit 13, below funnel 12, through a conduit 19. In this case the treating gases flow in a counter-current along path 180, as the heating and cooling gases, instead of flowing in parallel relationship with the compressed ovoids as shown in FIGURES 1 and 2.

It is apparent that the direction of the flow may be changed as desired in each of the treating zones and that 'the inlet and the outlet of the gases through the wall of the inner cylinder 2 may be arranged for one or for several of the other treating zones.

What I claim is:

A kiln for the thermal treatment of briquettes comprising a housing including a first cylinder concentric with and enclosed in a second cylinder, said first cylinder having a perforated opening near the center thereof, said cylinders being arranged in spaced relation to define an annular space therebetween, an opening at the upper end of said housing for permitting introduction of said briquettes into said annular space and an opening at the lower end of said housing for dis-charging said briquettes therefrom, a plurality of first baffle members having edge portions secured to the perimeter of said first cylinder and spaced in a vertical direction relative to each other, the alternate of said first bafi le members being perforated to allow gases to pass therethrough, a plurality of imperforate second bafile members having edge portions secured to the inner wall of said second cylinder and spaced in a vertical direction relative to each other, said first and second baffle members comprising a series, the alternate ones of which project in opposite directions, said first and second baflie members further arranged such that the free edge portion of said first bafiie members describe a series of circles of equal radius and the free edge portions of said second batfie members describe a series of equal circles of greater radius than that of said first baflie members with the free edge portions of all of said baffie members lying in a horizontal plane intersecting the point of attachment of the opposite set of battles, a first zone to heat the briquettes near the top of said kiln having inlet openings in said second cylinder near the upper end thereof for introducing the heating gases into said housing between the point of securement and free edge portions of the second bafiie member from the top of said second cylinder, whereby the gases pass below said second bafiie member upwardly through the briquettes, and one of the perforated bafi'le members mounted on said first cylinder, thence again through the briquettes, under the topmost baffle mounted on said second cylinder, and out through openings provided above the free edge portion of said topmost baffle member in the second cylinder whereupon the said gases exit from the kiln; a second Zone to treat said briquettes near the center of said kiln having inlet openings in said second cylinder near the center thereof for introducing gases to treat the briquettes between the point of securement and free edge portions of the third bafiie from the top of said second cylinder, whereby the gases pass below said third bafile member downwardly through the briquettes, through a second perforated bafiie member mounted on said first cylinder adjacent to said perforated opening in said first cylinder to selectively permit a portion of said treating gas to exit from the kiln through said first cylinder and the remaining treating gas through the briquettes under the fourth baffie member mounted on said second cylinder, and out through openings provided above the free edge portion of said fourth bafile member, a flap valve mounted within said first cylinder for controlling the amount of treating gases exiting through said first cylinder; a third zone to cool said briquettes prior to discharge from said kiln having inlet openings in said second cylinder near the bottom thereof for introducing cooling gases into said housing between the point of securement and free edge portions of the fifth bafi le member from the top of said second cylinder, whereby the gases pass below said fifth bafile member downwardly through the briquettes, through a third perforated baflle mounted on said first cylinder, thence again through the briquettes under the sixth baflie member mounted on said second cylinder, and out through openings provided above the free edge portion of said sixth bafile member in the second cylinder, whereby the briquettes receive homogeneous treatment to produce a uniform product.

References Cited by the Examiner UNITED STATES PATENTS 167,837 9/1875 Hunt 34-171 190,810 5/1877 Beach 34-171 308,475 11/1884 Eastwick 34-171 334,987 1/1886 Shedd 34-174 X 685,336 10/1901 Leroy et a1 263- 803,424 10/ 1905 Matcham 34171 1,685,338 9/1928 Randolph 34-170 2,069,192 1/1937 Behr et a1. 34-171 2,245,664 5/1941 Gronert 34-174 X 2,361,151 10/1944 Reed 34171 2,759,274 8/1956 Jonsson 34-170 X FOREIGN PATENTS 469,434 9/ 1914 France. 326,871 3/ 1930 Great Britain.

FREDERICK L. MATTESON, JR., Primary Examiner.

NORMAN YUDKOFF, JOHN J. CAMBY, Examiners.

J. SOFER, C. R. REMKE, Assistant Examiners. 

